Synchronous recovery of multiple valuable metals from municipal solid waste incineration fly ash and red mud via co-reduction technology

Abstract Municipal solid waste incineration fly ash (FA) and red mud (RM) are hazardous industrial solid wastes that pose potential environmental and safety risks if improperly stored or disposed of. Based on the physical and chemical properties of FA and RM, this study employs co-reduction technology to recover valuable metals while integrating a real-time GIS framework for spatial monitoring and disaster risk management. Under the optimal reduction conditions, the recovery rates of Fe, Ni, Cu, and Cr reach 76.55%, 84.89%, 73.95%, and 58.87%, respectively, with corresponding grades of 94.40%, 0.45%, 0.77%, and 0.42%. The FA content strongly affects the co-reduction process: insufficient FA (< 30%) limits carbon availability, while excessive FA (> 40%) increases calcium content and raises the system’s melting point by forming gehlenite. An appropriate FA/RM ratio effectively lowers the melting point and achieves the simultaneous formation of ferroalloy and glass structures. Under optimized conditions, the tailings consist mainly of amorphous SiO 2 –Al 2 O 3 –CaO–FeO glass phases, with leaching toxicity meeting environmental standards. By coupling co-reduction recovery with real-time GIS-based risk mapping and monitoring, this study establishes a sustainable route for metal recovery from hazardous wastes while enhancing disaster prevention and environmental management.